Gradient::platformGradient: Vector reserveCapacity -> reserveInitialCapacity
https://bugs.webkit.org/show_bug.cgi?id=115779

Reviewed by Andreas Kling.

* platform/graphics/cg/GradientCG.cpp:
(WebCore::Gradient::platformGradient): Clang is surprisingly smart at removing
all the branches of this function. Remove two more with reserveInitialCapacity.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@149927 268f45cc-cd09-0410-ab3c-d52691b4dbfc